Hacksaw.



J. C. DUNCAN.

HACKSAW.

APPLICATION FILED MAR. 2l. 1917. 1,292,275, Patented 111112119111 Fll JOHN C. DUNCAN, OF PITTSBURGH, PENNSYLVANIA.

HACKSAW.

Specification of Letters Patent.

Patented Jan. 21, 1919.

Application med March 21, 1917. serial No. 156,315.

To all 'whom'z't may concern:

Be it known that I, JOHN C. DUNCAN, a citizen of the United States, and resident of Pittsburgh, in the county of Allegheny and State of Pennsylvania, have invented certain new and usefulmprovements in Hacksaws, of which the following is a specication.

One object of the invention is to provide improved means for adjustably securing the blade to the saw frame, a primary purpose in this connection being to provide a construction wherein the adjusting device cooperates with a frame formed of metal of rectangular cross-section, avoiding the necessity of providin the frame with a socket for rotatably con 'ning the blade holding device as is usual with hacksaws now in general use.

A further object is to provide improved means for securing the saw blade with its cutting 'edge disposed either in the plane of the frame arch, or at right angles thereto as may be desired, the blade being secured in either position without rotating the devices to which either end of the blade is secured. The exact location of the blade in .either position in which it is to be used is means for either end of the blade.

Further objects of the invention are to provide improved means for securing the blade ends whereby accurate positioning and holding of the blade will be assured; to provide an adjustable frame of improved construction for accommodating blades of ditferent lengths; and for extending the bladeholding frame arms for depending the saw frame arch.

In the accompanying drawings, Figure 1 is a side elevation of a hacksaw constructed in accordance with the present invention, and Fig. 2 is a bottom edge view of the same. Fig. 2a is a detail of a portion of one of the blade-holding arms. Figs. 2b and 2 are similar views showing a 'slight modication. Fig. 3 is a sectional elevation of the connection between the adjustable frame arm and the back bar, and Fig. 4 is a cross section of the same taken on line 4*-4 of Fig. 1. Fig. 5 is a sectional detailofthe adjustable blade securing device and a portion of the handle for adjusting the same.

Fig. 6 is a sectional detail of the blade adjusting device taken on line 6-6 of Fig. 5.

vwork being done. tion simplifies the blade adjusting or blade changing operations, changes being made Fig. 7 is an inner 'end view of the blade adjusting device. Fig. 8 is an elevation of the hacksaw provided with arm extensions for carrying the blade and handle. Fig. 9 is a sectional detail taken on line 9 9 of Fig. 8, and Fig. 10 is a cross section taken on line 10-10 of Fig. 8.

Referring to the drawings, 2 designates the back bar of the saw frame from which roject the spaced arms 3 and 4 between w ich are secured the saw blade 5. Back bar 2 and at least one of arms 3 are preferably formed of a single piece of metal of rectangular cross section, and the other arm 4, here shown adjustably secured to the back bar for accommodating blades of different lengths, is also of similar cross section.

The means for adjustably securing the blade to arm 3 whereby the tension of the blade is regulated comprises a stem-like holding device 6 which is longitudinally slotted between its ends at 7 for slidably embracing arm 3, being held in position on the latter by removable stops or cleats 8. The outer end of device 6 is threaded at 9 for engagement with the internally threaded portion 10 of handle 11, and is provided with washer 11 having an angular hole to pass stem 6, saidwasher being adapted to bear against frame arm 3 for exerting thc required pull or tension on the holding device when tightening up the blade. With the blade holdin and adjusting means of the construction (there shown, it is unnecessary to form the frame arm with a socket for rotatably confining such device as has been the practice heretofore, thereby materially cheapening the cost and providin a stronger construction. Also with the ho ding means non-rotatable, it is always in accurate position for holding the blade with its cutting edge disposed accurately either in the plane of the arch, or at right angles thereto, depending on the character of the The improved construcmore expeditiously and with less effort than with hacksaws now in general use.

The saw blade is provided with perforations adjacent its opposite ends for engaging pins 12, 12 carried by arm 4 and similarly disposed pins 13, 13 carried by the inner end of holdin device 6. Pins 12 and 13 project laterally rom the frame for holding the blade with its cutting edge in the plane of the arch, as in Figs. 1 and 4, and pins 12 and 13 are utilized for holding the blade with its cutting edge at right angles to the plane of the arch. With the.

jects from said f ace in a-, backwardlyfin` clined direction. The same construction is characteristic of face 14 from which pin 13 extends, and is also true of the side face and end face of arm 4 from which `pins12 and 12 project as shown at 14u and 14h. Instead of placing the last mentioned pins in arm 4, they may be carried' by thelateral extension 4a of said arm, with the eXtension provided with the sloping faces as in Figs. 2b and 2C. The result is that the extremities of the blade when hooked over the appropriate pins and placed undertension are deflected in such manner as to insure tight engagement of theblade with theextremities of the sloping faces, the inclination of the pins forcing' the blade extremities into flat engagement with the sloping faces andjcausing the blade to tightly stretch over the edges of said faces in Ythe manner described, thereby insuring accurate and permanent alinement of the blade. Furthermore, the outer or higherlextremity o f face 14, or 14 is preferably notched to provide bearing points 15 against which theblade bears when under tension, thereby still further insuring its accurate position, as in Figs. 5 and 7,

For adjustably securing arm 4 to back bar 2, the bar embracing sleeve-like portion 4 of said arm is formed with the transverse circular pin passage 16 which is adapted to register with one or another of the curved notches 2 in the edge of bar 2, so thatwhen passage 16 and one of the notches are in alineinent, a through circular passage is formed, whereas when they are not inalinement, pinrpassage 16 is intersected by the back bar. A pin 17 rotatable in passage 16 is partially circular and partially flat, as shown in Figs. 1, 3 and 4, with the result that when the circular portion is turned into engagement with one of notches -2,arm 4 is locked on the back bar, whereas when. the

pin is turned to place its fiat surface 17 toward the backbaiythe latter is disengaged and arm 4 is free to slide thereon in either direction.

For increasing the depth of the frame arch andl thereby adapting the same foruse on relatively deep or thick Work in which an arch of considerable expanse is required, the blade carrying arms are provided with extensionL pieces 18l as in Figs.y 8, 9' andi-10, one of these pieces splicingv ontol the side face of arm 4 on which there are -no bladeholding pins, and the other piece is similarly secured to the face of arm 3Y back of stops 8. Each of' pieces 1'8 carries an arm-em-V bracing socket 19, the open side of' which may be closed by the swinging catch. 20 which is secured inV closed position by the set screw 20. One of the extensionpieces is provided with pins 12 and 12b for securing the outer end of the blade,`and the other extension piece is provided with removable stops 8a for slidably coiining the blade holder 6. To change from the arrangement shown in Fig, l to that in Fig,4 8it is only necessary to relaxand detach the blade and then remove the lowermost stop 8, whereupon the adjustable blade-holding device may be removed, and then after the extension pieces 18.h ave been applied,

the blade and its holding device may be mounted ony the extremities. thereof as in Fig. 8, exactly the same way as whenthe extension pieces. are not in use.v

If claim In a hacksaw andinconibination with al saw blade having perforated ends,a frame having supporting arms one of which is provided with two saw contacting faces con-l structed so as tov stand at an angle tofthe JOHN C; DUNCAN..

Witnesses E.' B. MOLTER, Amon B. Dici).

Gopiems of this patent may he obtained for ve cents each, by addressing the Commissioner of Patents, Washington, B., G'. 

